| Message ID | 20191204123714.27765-2-andreas.rheinhardt@gmail.com |
|---|---|
| State | Accepted |
| Commit | bc3cf2bbd320e1ade2791dca02b9ba947ca436ab |
| Headers | show |
On Wed, Dec 04, 2019 at 01:37:13PM +0100, Andreas Rheinhardt wrote: > vobsub_read_header() uses an AVBPrint to write a string and up until > now, it collected the string stored in the AVBPrint via > av_bprint_finalize(), which might involve an allocation and copy of the > string. But this is unnecessary, as the lifetime of the returned string > does not exceed the lifetime of the AVBPrint. So use the string in the > AVBPrint directly. > > This also makes it possible to easily fix a memleak: In certain error > situations, the string stored in the AVBPrint would not be freed (if it > was dynamically allocated). This has been fixed, too. > > Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com> > --- > Supersedes https://ffmpeg.org/pipermail/ffmpeg-devel/2019-October/252074.html > Resending because of merge conflict. will apply thx [...]
Michael Niedermayer: > On Wed, Dec 04, 2019 at 01:37:13PM +0100, Andreas Rheinhardt wrote: >> vobsub_read_header() uses an AVBPrint to write a string and up until >> now, it collected the string stored in the AVBPrint via >> av_bprint_finalize(), which might involve an allocation and copy of the >> string. But this is unnecessary, as the lifetime of the returned string >> does not exceed the lifetime of the AVBPrint. So use the string in the >> AVBPrint directly. >> >> This also makes it possible to easily fix a memleak: In certain error >> situations, the string stored in the AVBPrint would not be freed (if it >> was dynamically allocated). This has been fixed, too. >> >> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com> >> --- >> Supersedes https://ffmpeg.org/pipermail/ffmpeg-devel/2019-October/252074.html >> Resending because of merge conflict. > > will apply > > thx > Thanks. During checking whether my patches work I have also found a use of uninitialized values in vobsub_read_packet() [1]; and earlier I have found a way to eliminate the secondary packet when reading VobSub [2]. Could you look over them, too? - Andreas [1]: https://ffmpeg.org/pipermail/ffmpeg-devel/2019-October/251961.html [2]: https://ffmpeg.org/pipermail/ffmpeg-devel/2019-October/251146.html
diff --git a/libavformat/mpeg.c b/libavformat/mpeg.c index 80983f8a81..e4fe16c7d2 100644 --- a/libavformat/mpeg.c +++ b/libavformat/mpeg.c @@ -718,7 +718,6 @@ static int vobsub_read_header(AVFormatContext *s) int i, ret = 0, header_parsed = 0, langidx = 0; VobSubDemuxContext *vobsub = s->priv_data; size_t fname_len; - char *header_str = NULL; AVBPrint header; int64_t delay = 0; AVStream *st = NULL; @@ -731,8 +730,7 @@ static int vobsub_read_header(AVFormatContext *s) char *ext; vobsub->sub_name = av_strdup(s->url); if (!vobsub->sub_name) { - ret = AVERROR(ENOMEM); - goto end; + return AVERROR(ENOMEM); } fname_len = strlen(vobsub->sub_name); @@ -740,24 +738,23 @@ static int vobsub_read_header(AVFormatContext *s) if (fname_len < 4 || *(ext - 1) != '.') { av_log(s, AV_LOG_ERROR, "The input index filename is too short " "to guess the associated .SUB file\n"); - ret = AVERROR_INVALIDDATA; - goto end; + return AVERROR_INVALIDDATA; } memcpy(ext, !strncmp(ext, "IDX", 3) ? "SUB" : "sub", 3); av_log(s, AV_LOG_VERBOSE, "IDX/SUB: %s -> %s\n", s->url, vobsub->sub_name); } if (!(iformat = av_find_input_format("mpeg"))) { - ret = AVERROR_DEMUXER_NOT_FOUND; - goto end; + return AVERROR_DEMUXER_NOT_FOUND; } vobsub->sub_ctx = avformat_alloc_context(); if (!vobsub->sub_ctx) { - ret = AVERROR(ENOMEM); - goto end; + return AVERROR(ENOMEM); } + av_bprint_init(&header, 0, INT_MAX - AV_INPUT_BUFFER_PADDING_SIZE); + if ((ret = ff_copy_whiteblacklists(vobsub->sub_ctx, s)) < 0) goto end; @@ -767,7 +764,6 @@ static int vobsub_read_header(AVFormatContext *s) goto end; } - av_bprint_init(&header, 0, INT_MAX - AV_INPUT_BUFFER_PADDING_SIZE); while (!avio_feof(s->pb)) { char line[MAX_LINE_SIZE]; int len = ff_get_line(s->pb, line, sizeof(line)); @@ -888,22 +884,20 @@ static int vobsub_read_header(AVFormatContext *s) } if (!av_bprint_is_complete(&header)) { - av_bprint_finalize(&header, NULL); ret = AVERROR(ENOMEM); goto end; } - av_bprint_finalize(&header, &header_str); for (i = 0; i < s->nb_streams; i++) { AVCodecParameters *par = s->streams[i]->codecpar; ret = ff_alloc_extradata(par, header.len); if (ret < 0) { goto end; } - memcpy(par->extradata, header_str, header.len); + memcpy(par->extradata, header.str, header.len); } end: - av_free(header_str); + av_bprint_finalize(&header, NULL); return ret; }
vobsub_read_header() uses an AVBPrint to write a string and up until now, it collected the string stored in the AVBPrint via av_bprint_finalize(), which might involve an allocation and copy of the string. But this is unnecessary, as the lifetime of the returned string does not exceed the lifetime of the AVBPrint. So use the string in the AVBPrint directly. This also makes it possible to easily fix a memleak: In certain error situations, the string stored in the AVBPrint would not be freed (if it was dynamically allocated). This has been fixed, too. Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com> --- Supersedes https://ffmpeg.org/pipermail/ffmpeg-devel/2019-October/252074.html Resending because of merge conflict. libavformat/mpeg.c | 22 ++++++++-------------- 1 file changed, 8 insertions(+), 14 deletions(-)